The following discussion is provided solely to assist the understanding of the reader, and does not constitute an admission that any of the information discussed or references cited constitute prior art to the present invention.
Certain clamp type jigs for use with rotary tools having cutting bits have been described. U.S. Pat. No. D160,734 and U.S. Pat. No. 2,522,400 to Polkosnik show a doweling jig having a carriage slideable on two parallel rails connected between two stationary members. A significant problem with the clamp type jigs such as Polkosnik's is that they are designed to guide drill bits for making holes for receiving dowels and are not suitable for guiding a plunge router to form a slot mortise that would typically receive a tenon such as would be desirable for the construction of frame-type furniture.
U.S. Pat. No. 5,154,214 to Hagerman describes a mortising jig for use with a router or other tool to form finish or shallow mortises for mounting hardware. A significant problem with existing clamp type mortising jigs such as Hagerman's is that they are designed for making mortises for hardware and are not suitable for forming mortises for receiving tenons as would be desirable for use in frame-type furniture construction.